Manufacture of artificial silk



E. MENGERINGHAUSEN ET AL MANUFACTURE OF ARTIFICIAL SILK Dec. 5, 1939. j 2,182,762

Filed NOV. 21, 1956 Patented Dec. 5, 1939 PATENT OFFICE 2,182,762 7 MANUFACTURE or ARTIFICIAL sm;

Ernst Mengeringhausen, Oberbruch, and Franz Berndt, Sydcwsane, near Stettin, Germany, assignors to North AmericanRayon Corporation, New York, N. Y., a corporation of Delaware Application November 21, 1936, Serial No. 112,046 In Germany November 25, 1935 4 Claims.

The present invention relates to the manufacture of yarn of artificial origin in accordance with the wet-spinning process, but primarily is concerned with a device for the controlled stretching of freshly extruded artificial silk threads.

In the manufacture of artificial silk by the wet-spinning process, the spinning solution is extruded through spinnerettes into a precipitating bath which hardens the freshly formed threads. The problem with which the artificial silk industry has always been confronted is the nonuniform shrinkage of the inside and outside portions forming a wound yarn package, which'results in dyeing differences in the finished product.

In order to compensate the differences of tension caused by the irregular shrinkage of the various yarn layers comprising a wound body, it has hitherto been suggested to gradually stretch the spun thread prior to the winding thereof, which was carried out by means of guiding the thread, prior to its winding upon a collecting device, around a brake rod which through constant shifting changes the angle formed by the path of the thread, so that a gradually increasing stretching of the latter was obtained. However, evenif the shifting of the brake rod is perfectly uniform, it is still not possible to avoid intermittent variations of the braking resistance, caused by alternate stretching and slipping of the thread as it passes around the brake or tension rod, thus resulting in a considerable variation in the structure of the thread. Consequently, a brake rod is at best unreliable and to a great extent an uncontrollable device for the regulation of the stretching of threads.

It is also known to guide thefreshly spun thread before being collected in a spin pot or collecting device over two positively driven rollers which as the spinning process progresses effect a gradually increasing stretching of the thread. The rotating speed of the two rollers can be accurately adjusted so that the increasing stretching of the thread is clearly fixed and intermittent variations of tension are eliminated. Compared with the ordinary pot spinning and spool spinning machines, however, this arrangement has the disadvantage that it requires the use of two positively driven rollers.

Furthermore, in order to eliminate dyeing differences caused by irregular shrinkage of the yarn wound upon spools, it has been proposed to vary the speed of the winding spool in relation to that of the take-up roller. The winding spool was either made to rotate slow at the beginning.

and faster at the end of winding, while the take- 'up roller maintained a'uniform speed, or the take-up roller was made to rotate fast at the beginning and slower at the end of winding, while the winding spool maintains a uniform speed. v

g It is therefore an object of the present invention to devise a process and apparatus which will greatly simplify the spinning of yarn of even dyeing qualities.

Another object of the present invention is to devise a means which may be easily adapted for use in spinning machines now employed in the industry.

A further object of the present invention is to devise a drawing roller which will take the place of two driven rollers as is now common in the art.

' A still further object of the present invention is todevise a means for uniformly controlling the change of tension whereby uneven'shrinkage in the yarn body is compensated for with resultant 'yarn or filaments of 'even dyeing qualities.

A still further object lies in the assurance of obtaining a perfectly uniform, accurately predeterminable increase of tension.

These and other objects will in part become obvious and in part be pointed out from a'study of the following specification and attached claims takenin conjunction with the accompanying drawing in which Fig. 1 is a side elevation of the new device, and

Fig. 2 is an end view thereof, and f Fig. 3 is a side elevation of a modified form of the new device. a

Fig. 4 is a side elevation of another modified form of the new device.

In the drawing, in which like numerals indicate like parts, the thread 2 extruding from the spinnerette I is drawn off by the stepped roller 3, passed around the latter a plurality of times and then collected in the spin pot 4. The stepped roller 3 comprises a conical surface 5 and a cylindrical surface 6. The thread first contacts with the conical portion 5 of the roller 3 and is wound a plurality of times around the large diameter a thereof. By means of the thread guide I the thread is then passed to the cylindrical portion 6 of the stepped roller 3. After being wound around the latter a plurality of times it is led to the spin pot 4.

Owing to the passing of the thread from the of the thread is gradually increased which is accomplished by gradually shifting the thread from the large diameter a of the portion to the small diameter b thereof. The shifting of the thread may be effected through the axial displacement of the stepped roller 3 while the thread guide 8 remains stationary, or the latter may be axially displaced while the stepped roller remains stationary.

The stretching of the thread is just so much increased as is necessary to overcome the irregu lar shrinkage of the yarn which causes dyeing differences.

Owing to the fact that the circumferential speed of the portion 5 is smaller atb than at a and because the thread is gradually shifted from the large diameter a to the smaller diameter 1), the denier of the thread is gradually increased. However, because of the increased stretching of the thread taking place between the portion 5 and the portion 6 the said increase of denieris practically abolished, so that a thread having a uniform denier throughout is obtained.

The stepped roller may alsobe so constructed that the diameter a of the conical surface 5 is as large as that of the surface 6; or it may even be somewhat larger than the latter. In the first case the thread on passing from surface'5 to surface 6 is first not stretched but only as the spinning process progresses, while in the second case the tension exerted on the thread is at first even somewhat reduced; n

Reference is now had to Fig. 3 of the drawing winch is a modified form of the new invention. Since, as is well known, not only dyeing differences are the result of irregular shrinkage of the spun cake, but also variations of the denier of thread, Fig. 3 discloses a device which will eliminate these irregularities. By makingl the surface 5 cylindrical and the surface 5 conical, i. e., the latter would be larger in diameter than the former, and by first leading the freshly extruded thread around the cylindrical portion, the thread is drawn from the spinnerette in a uniform denier because the circumferential speed of the cylindrical portion remains uniform throughout the entire spinning process. After passing around the cylindrical portion a plurality of times, the thread is led to the larger conical surface, If the thread is now slowly shifted from the small diameter of the latter to the larger diameter thereof, the thread is not only increasingly stretched but at the same time gradually reduced in denier.

Having now described the new invention as required by the Patent Statutes, what is claimed is:

1. In an apparatus for use in the manufacture of yarn of artificial origin, a combination comprising a spinnerette for extruding the thread, a means for collecting a thread into a yarn body, a driven roller positioned between said spinnerette and said collecting means, said driven roller having different diameter surfaces, one of said surfaces being shaped to conform to a frusto cone and the other being of a cylindrical shape, means to guide said thread over said surfaces and means to vary the position of said thread on said conical surface as the yarn body is built up.

2. A device for the uniform stretching of freshly extruded threads of artificial origin, comprising a stepped roller adapted to draw off a freshly extruded thread, one step of said stepped roller comprising a conical roller and the second step of said stepped roller comprising a cylindrical roller, said conical roller being smaller in diameter than said cylindrical roller, guiding means adapted to guide said thread around the surfaces of said stepped roller, and means to vary the position of said thread on said conical surface as the yarn body is built up.

3. A device of the class set forth comprising a stepped roller adapted to throw off a freshly extruded thread, one step of said stepped roller comprising a cylindrical roller and the other step of said stepped roller comprising a conical roller, said cylindrical roller being smaller in diameter than said conical roller, guiding means adapted to guide said thread around the surfaces of said stepped roller, and means to vary the position of said thread on said conical surface as said body is built up.

4. A device of the class set forth comprising a stepped roller adapted to draw off a freshly extruded thread, one step of said stepped roller comprising a conical surface and the second step thereof comprising a cylindrical surface, the smallest diameter of said conical surface being of the same size as the diameter of said cylindrical surface, guiding means adapted to guide said thread around the surfaces of said stepped roller, and means to vary the relative position of said conical surface and said guiding means.

ERNST MENGERINGHAUSEN. FRANZ BERNDT. 

